Friday, January 02, 2009

Sleep and coronary artery calcification

Several medical bloggers have posted about a recent study in which increased sleep time was associated with a decreased incidence of coronary artery disease (as measured by coronary artery calcification).

The problem with these observational studies looking at sleep duration and mortality/morbidity is that they don't distinguish between 1) voluntary sleep deprivation, 2) primary insomnia, and 3) insomnia secondary to medical/sleep disorders.

How is a doctor to use the data from this study???I doubt writing a prescription for a sleeping pill would improve someone's coronary artery calcification score. However, advising someone with voluntary sleep deprivation (due to work pressures, etc) to extend their sleep hours might (if they take your advice)- I base this conclusion on prior studies which demonstrated that voluntary sleep restriction does lead to adverse metabolic consequences. And of course, treating any obstructive sleep apnea present is important, especially in patients with pre-existing coronary artery disease, atrial fibrillation, or congestive heart failure.